Shared antigenic determinants among alcohol dehydrogenase and other enzymes

Immune sera raised in rabbits against denatured alcohol dehydrogenase (ADH) isozymes of class I from horse liver and class III from human placenta were found to cross-react with the subunits of other dehydrogenases from various sources. Similarities in the primary structure of some of these enzymes with horse ADH can account for the observed cross-reactivity. The cross-reactivity of the same antisera with other enzymes suggests that some structures within the ADH molecule have been preserved over a long evolutionary period. The immune sera were also found to react with some of the tested enzymes in their native conformations, suggesting that they contained antibodies directed against 'sequential' epitopes expressed on the surface of the proteins when folded in the native state.